1. Field of the Invention
The present invention relates to a battery unit, and more particularly to a battery unit applied to an electric vehicle that travels by driving a motor with power of a battery.
2. Description of Related Art
An assembled battery formed by collecting plural battery cells, i.e., a so-called battery module, is used as a battery for supplying power to a motor of an electric vehicle.
JP Patent No. 4242665 describes a battery unit that includes a battery module having a generally rectangular solid shape and formed by stacking tabular battery cells with a certain thickness, in a longitudinal direction of a vehicle body, wherein a size in a vertical direction of the battery module is smaller than sizes of the battery module in the longitudinal direction and a vehicle width direction. The battery unit is configured so that cooling air is passed through, in the vehicle width direction of the battery module, through a gap between the battery cells to cool the battery module.
The technology described in JP Patent No. 4242665 provides the structure in which both end faces of the battery module are connected by a plate-like member extending in a stacking direction of the battery cell in order to maintain a positional relationship between the battery cells. However, JP Patent No. 4242665 does not describe a countermeasure for the situation in which each battery cell expands due to the temperature rise or secular change. When the structure of preventing the expansion of the battery module is applied, there arises a problem of an increase in size of the battery unit or an increase in the number of components.